Recovery of metals from worn-out articles, particularly automotive vehicles, by means of crushers or grinders, is generally effected by introducing the articles into a hammer mill which tears and cuts up the material entering into the said mill, by interaction with one or several anvils, and which ejects and/or evacuates through sifting walls the resulting mechanical chips having a predetermined caliber.
In known mills, the hammers are generally mounted on a rotor constituted by an assembly of discs separated by crosspieces at the level of the fixation of the hammers which are eclipsable in the rotor and which turn freely about their axis of fixation. During operation, these hammers are subjected to wear and must accordingly be mounted in an invertible manner on their spindle, so as to prolong their useful life. To prevent such an inversion of the mounting, it has also been proposed to drive the rotor in a reversible manner.
Finally, depending on the materials to be milled, a greater or lesser number of hammers must be operated which consequently requires, upon each change of the material to be milled, an intervention on the rotor so as to mount or dismount a certain number of the hammers. Such interventions, however, present the disadvantage of relatively long down time of the machine, which considerably increases maintenance costs.